Collateral drying process

Abstract

A method of utilizing waste heat from a fuel-fired electrical power generation or steam raising plant, wherein flue gas from said plant is conducted through a heat exchange zone in contact with relatively cool wet material for making Portland cement.

What is claimed is: 
     
       1. The method of increasing the efficiency of Portland cement manufacture, which comprises the steps of: (a) firing a heat generating unit in an electrical power generation plant with fuel and air to generate electrical power and a continuous stream of flue gas at temperature in excess of 130° C;   (b) directly contacting the flue gas of step (a) with an aqueous slurry of Portland cement raw material for a time sufficient to produce a free-flowing solid powder which is Portland cement raw meal;   (c) treating the flue gas effluent from step (b) to separate entrained dust therefrom and then discharging the gas to the atmosphere; and   (d) introducing the raw meal of step (b) into one end of a rotary kiln in a Portland cement making plant and firing the kiln with fuel and air in amount sufficient to discharge Portland cement clinker from the other end of said kiln.   
     
     
       2. The method as defined in claim 1 wherein said electrical power generating plant and said Portland cement making plant are remotely situated, and including the step of transporting the raw meal of step (b) from the power generating plant to the cement making plant. 
     
     
       3. The method as defined in claim 2 including the step of transporting the slurry of step (b) from the cement making plant to the power generating plant. 
     
     
       4. The method as defined in claim 1 wherein the electrical power generating plant and the Portland cement making plant are in close proximity and including the step of admixing the gaseous effluent from said kiln with the flue gas effluent of step (b) and treating them simultaneously in step (c). 
     
     
       5. The method as defined in claim 1 wherein the flue gas and slurry of step (b) are contacted in a spray drier. 
     
     
       6. The method as defined in claim 2 wherein the flue gas and slurry of step (b) are contacted in a spray drier. 
     
     
       7. The method as defined in claim 3 wherein the flue gas and slurry of step (b) are contacted in a spray drier. 
     
     
       8. The method as defined in claim 4 wherein the flue gas and slurry of step (b) are contacted in a spray drier.